U.S. patent application number 17/010983 was filed with the patent office on 2021-03-18 for method of etching silicon oxide film and plasma processing apparatus.
This patent application is currently assigned to Tokyo Electron Limited. The applicant listed for this patent is Tokyo Electron Limited. Invention is credited to Koki CHINO, Yoshimitsu KON, Satoshi YAMADA.
Application Number | 20210082712 17/010983 |
Document ID | / |
Family ID | 1000005108885 |
Filed Date | 2021-03-18 |
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United States Patent
Application |
20210082712 |
Kind Code |
A1 |
CHINO; Koki ; et
al. |
March 18, 2021 |
METHOD OF ETCHING SILICON OXIDE FILM AND PLASMA PROCESSING
APPARATUS
Abstract
A disclosed method etches a silicon oxide film of a substrate on
which a mask is provided. The method includes performing first
plasma processing on a substrate by using a first plasma formed
from a first processing gas including a fluorocarbon gas, a
fluorine-free carbon-containing gas, and an oxygen-containing gas.
The method further includes performing second plasma processing on
the substrate by using a second plasma formed from a second
processing gas including a fluorocarbon gas. A temperature of the
substrate during the first plasma processing is lower than the
temperature of the substrate during the second plasma
processing.
Inventors: |
CHINO; Koki; (Kurokawa-gun,
JP) ; YAMADA; Satoshi; (Kurokawa-gun, JP) ;
KON; Yoshimitsu; (Kurokawa-gun, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tokyo Electron Limited |
Tokyo |
|
JP |
|
|
Assignee: |
Tokyo Electron Limited
Tokyo
JP
|
Family ID: |
1000005108885 |
Appl. No.: |
17/010983 |
Filed: |
September 3, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01J 37/32724 20130101;
H01L 21/31116 20130101; H01J 2237/334 20130101; H01J 37/32449
20130101; H01L 21/67069 20130101; H01J 37/32082 20130101; H01L
21/31144 20130101 |
International
Class: |
H01L 21/311 20060101
H01L021/311; H01L 21/67 20060101 H01L021/67; H01J 37/32 20060101
H01J037/32 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 17, 2019 |
JP |
2019-168083 |
Claims
1. A method of etching a silicon oxide film of a substrate having
the silicon oxide film and a mask provided on the silicon oxide
film, the method comprising: (a) performing first plasma processing
on the substrate by using a first plasma formed from a first
processing gas including a fluorocarbon gas, a fluorine-free
carbon-containing gas, and an oxygen-containing gas, wherein a
temperature of the substrate is set to a first temperature during
the first plasma processing, and a carbon-containing substance is
deposited on the mask and the silicon oxide film is etched by the
first plasma processing; and (b) performing second plasma
processing on the substrate by using a second plasma formed from a
second processing gas including a fluorocarbon gas after (a),
wherein the temperature of the substrate is set to a second
temperature during the second plasma processing, and the silicon
oxide film is etched by the second plasma processing, wherein the
first temperature is lower than the second temperature.
2. The method according to claim 1, wherein the first processing
gas and the second processing gas are the same processing gas.
3. The method according to claim 1, wherein (a) and (b) are
performed by using a plasma processing apparatus, and wherein a
radio frequency power used to generate the first plasma in the
plasma processing apparatus in (a) is lower than a radio frequency
power used to generate the second plasma in the plasma processing
apparatus in (b).
4. The method according to claim 1, wherein in (a) and (b), an
amount of electric power of a heater in a substrate support that
supports the substrate is adjusted such that the first temperature
is lower than the second temperature.
5. The method according to claim 1, wherein the fluorine-free
carbon-containing gas is CO gas, and the oxygen-containing gas is
02 gas.
6. The method according to claim 1, wherein the mask is a mask
formed of an organic material.
7. A plasma processing apparatus comprising: a chamber; a substrate
support provided in the chamber; a gas supply unit configured to
supply a first processing gas including a fluorocarbon gas, a
fluorine-free carbon-containing gas, and an oxygen-containing gas,
and a second processing gas including a fluorocarbon gas, into the
chamber; a radio frequency power supply configured to generate
radio frequency power for generating plasma from gas in the
chamber; and a controller configured to control the gas supply unit
and the radio frequency power supply, wherein the controller
performs first control to control the gas supply unit to supply the
first processing gas into the chamber and control the radio
frequency power supply to generate a first plasma from the first
processing gas in the chamber, to etch a silicon oxide film of a
substrate and to form a carbon-containing deposit on a mask of the
substrate provided on the silicon oxide film, performs second
control to control the gas supply unit to supply the second
processing gas into the chamber and control the radio frequency
power supply to generate a second plasma from the second processing
gas in the chamber, to further etch the silicon oxide film, and
sets a temperature of the substrate in the first control to a
temperature lower than a temperature of the substrate which is set
in the second control.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims the benefit of
priority from Japanese Patent Application No. 2019-168083 filed on
Sep. 17, 2019, the entire contents of which are incorporated herein
by reference.
FIELD
[0002] Exemplary embodiments of the present disclosure relate to a
method of etching a silicon oxide film and a plasma processing
apparatus.
BACKGROUND
[0003] Plasma etching of a silicon oxide film is used to transfer a
pattern of a mask to the silicon oxide film. Japanese Patent
Application Laid-Open Publication No. 2011-204999 (hereinafter
referred to as "Patent Document 1") discloses plasma etching of a
silicon oxide film. In the plasma etching described in Patent
Document 1, the silicon oxide film is etched by using plasma formed
from a fluorocarbon gas.
SUMMARY
[0004] In an exemplary embodiment, a method of etching a silicon
oxide film of a substrate is provided. The substrate has the
silicon oxide film and a mask. The mask is provided on the silicon
oxide film. The method includes (a) performing first plasma
processing on the substrate by using a first plasma formed from a
first processing gas. The first processing gas includes a
fluorocarbon gas, a fluorine-free carbon-containing gas, and an
oxygen-containing gas. A temperature of the substrate is set to a
first temperature during the first plasma processing. A
carbon-containing substance is deposited on the mask and the
silicon oxide film is etched by the first plasma processing. The
method further includes (b) performing second plasma processing on
the substrate by using a second plasma formed from a second
processing gas including a fluorocarbon gas, after the operation
(a). The temperature of the substrate is set to a second
temperature during the second plasma processing. The silicon oxide
film is etched by the second plasma processing. The first
temperature is lower than the second temperature.
[0005] The foregoing summary is illustrative only and is not
intended to be in any way limiting. In addition to the illustrative
aspects, exemplary embodiments, and features described above,
further aspects, exemplary embodiments, and features will become
apparent by reference to the drawings and the following detailed
description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a flow chart of a method of etching a silicon
oxide film according to one exemplary embodiment.
[0007] FIG. 2 is a partially enlarged cross-sectional view of an
exemplary substrate.
[0008] FIG. 3 is a partially enlarged cross-sectional view of an
exemplary substrate.
[0009] FIG. 4 is a diagram schematically showing a plasma
processing apparatus according to an exemplary embodiment.
[0010] FIG. 5A is a partially enlarged cross-sectional view of the
exemplary substrate in a state after performing a step STa of the
method shown in FIG. 1, and FIG. 5B is a partially enlarged
cross-sectional view of an exemplary substrate in a state after
performing a step STb of the method shown in FIG. 1.
[0011] FIG. 6 is a partially enlarged cross-sectional view of the
exemplary substrate in a state after performing a step STc of the
method shown in FIG. 1.
[0012] FIG. 7A is a partially enlarged cross-sectional view of the
exemplary substrate in a state after performing a step ST1 of the
method shown in FIG. 1, and FIG. 7B is a partially enlarged
cross-sectional view of an exemplary substrate in a state after
performing a step ST2 of the method shown in FIG. 1.
DETAILED DESCRIPTION
[0013] Hereinafter, various exemplary embodiments will be
described.
[0014] In an exemplary embodiment, a method of etching a silicon
oxide film of a substrate is provided. The substrate has the
silicon oxide film and a mask. The mask is provided on the silicon
oxide film. The method includes (a) performing first plasma
processing on the substrate by using a first plasma formed from a
first processing gas. The first processing gas includes a
fluorocarbon gas, a fluorine-free carbon-containing gas, and an
oxygen-containing gas. A temperature of the substrate is set to a
first temperature during the first plasma processing. A
carbon-containing substance is deposited on the mask and the
silicon oxide film is etched by the first plasma processing. The
method further includes (b) performing second plasma processing on
the substrate by using a second plasma formed from a second
processing gas including a fluorocarbon gas, after the operation
(a). The temperature of the substrate is set to a second
temperature during the second plasma processing. The silicon oxide
film is etched by the second plasma processing. The first
temperature is lower than the second temperature.
[0015] In a case where the temperature of the substrate is set to a
relatively low temperature, a relatively large amount of
carbon-containing material is deposited on the surface of the
substrate from the plasma. Therefore, as a result of the first
plasma processing, a relatively large amount of carbon-containing
material is deposited on the mask. In addition, the silicon oxide
film is etched by the fluorine species from the first plasma during
the first plasma processing. While performing the second plasma
processing, the silicon oxide film is further etched by the
fluorine species from the second plasma. On the other hand, the
mask is protected while performing the second plasma processing by
the carbon-containing material deposited on the mask as a result of
the first plasma processing. Hence, according to the method
according to the above-described embodiment, it is possible to
suppress the decrease in film thickness of the mask due to the
etching of the silicon oxide film.
[0016] In an exemplary embodiment, the first processing gas and the
second processing gas may be the same processing gas.
[0017] In an exemplary embodiment, the operation (a) and the
operation (b) may be performed by using a plasma processing
apparatus. A radio frequency power used to generate the first
plasma in the plasma processing apparatus in the operation (a) may
be lower than a radio frequency power used to generate the second
plasma in the plasma processing apparatus in the operation (b). In
a case where a small radio frequency power is used, the density of
the plasma becomes low and the amount of heat given to the
substrate from the plasma becomes small. According to the
embodiment, the temperature of the substrate W is set to the first
temperature while performing the first plasma processing and is set
to the second temperature while performing the second plasma
processing.
[0018] In an exemplary embodiment, an amount of electric power of a
heater in a substrate support that supports the substrate may be
adjusted such that the first temperature is lower than the second
temperature, in the operation (a) and the operation (b).
[0019] In an exemplary embodiment, in the first processing gas, the
fluorine-free carbon-containing gas may be CO gas and the
oxygen-containing gas may be O.sub.2 gas.
[0020] In an exemplary embodiment, the mask may be a mask formed of
an organic material.
[0021] In another exemplary embodiment, a plasma processing
apparatus is provided. The plasma processing apparatus includes a
chamber, a substrate support, a gas supply unit, a radio frequency
power supply and a controller. The substrate support is provided in
the chamber. The gas supply unit is configured to supply a first
processing gas and a second processing gas into the chamber. The
first processing gas includes a fluorocarbon gas, a fluorine-free
carbon-containing gas, and an oxygen-containing gas. The second
processing gas includes a fluorocarbon gas. The radio frequency
power supply is configured to generate radio frequency power for
generating plasma from gas in the chamber. The controller is
configured to control the gas supply unit and the radio frequency
power supply. The controller performs first control to control the
gas supply unit to supply the first processing gas into the chamber
and control the radio frequency power supply to generate a first
plasma from the first processing gas in the chamber. The first
control is performed to etch a silicon oxide film of a substrate
and to form a carbon-containing deposit on a mask of the substrate
provided on the silicon oxide film. The controller performs second
control to control the gas supply unit to supply the second
processing gas into the chamber and control the radio frequency
power supply to generate a second plasma from the second processing
gas in the chamber, to further etch the silicon oxide film. The
controller sets a temperature of the substrate in the first control
to a temperature lower than a temperature of the substrate which is
set in the second control.
[0022] Hereinafter, various exemplary embodiments will be described
in detail with reference to the drawings. In the drawing, the same
or equivalent portions are denoted by the same reference
symbols.
[0023] FIG. 1 is a flow chart of a method of etching a silicon
oxide film according to one exemplary embodiment. The method shown
in FIG. 1 (hereinafter referred to as "method MT") is performed to
etch the silicon oxide film on the substrate. The method MT
includes a step ST1 and a step ST2.
[0024] FIG. 2 is a partially enlarged cross-sectional view of an
exemplary substrate. The steps ST1 and ST2 of the method MT can be
applied to the substrate W shown in FIG. 2. The substrate W shown
in FIG. 2 has a silicon oxide film OX and a mask MK. The substrate
W may further have an underlying region UR. The silicon oxide film
OX may be provided on the underlying region UR. The mask MK is
provided on the silicon oxide film OX. The mask MK has a pattern
transferred to the silicon oxide film OX by etching. That is, the
mask MK provides an opening that partially exposes the surface of
the silicon oxide film. The mask MK is made of, for example, an
organic material. However, the mask MK may be formed of any
material as long as the etching rate of the silicon oxide film OX
is higher than the etching rate of the mask MK.
[0025] FIG. 3 is a partially enlarged cross-sectional view of an
exemplary substrate. In an embodiment, the substrate W may have a
configuration shown in FIG. 3 before the steps ST1 and ST2 are
applied thereto. The substrate W shown in FIG. 3 further has an
organic film OF, a SiON film SF, an antireflection film AF, and a
resist mask RM. The organic film OF is provided on the silicon
oxide film OX. The organic film OF is formed of an organic
material. The organic film OF is, for example, an amorphous carbon
film. The SiON film SF is provided on the silicon oxide film OX.
The antireflection film AF is made of an organic material and is
provided on the silicon oxide film OX. The resist mask RM is a
photoresist mask and is provided on the antireflection film AF. The
resist mask RM has a pattern for forming the mask MK from the
organic film OF. The resist mask RM is patterned by using, for
example, the photolithography technique. The method MT may further
include steps STa to STd to obtain the substrate W in the state
shown in FIG. 2 from the substrate W in the state shown in FIG.
3.
[0026] In an embodiment, the method MT is performed using a plasma
processing apparatus. FIG. 4 is a diagram schematically showing a
plasma processing apparatus according to an exemplary embodiment.
The plasma processing apparatus 1 shown in FIG. 4 includes a
chamber 10. The chamber 10 provides an internal space 10s therein.
The chamber 10 includes a chamber body 12. The chamber body 12 has
substantially cylindrical shape. The chamber body 12 is made of,
for example, aluminum. A film having corrosion resistance is formed
on an inner wall surface of the chamber body 12. The film may be
ceramics such as aluminum oxide or yttrium oxide.
[0027] A passageway 12p is formed in a sidewall of the chamber body
12. The substrate W is transferred between the internal space 10s
and the outside of the chamber 10 through the passageway 12p. The
passageway 12p is opened or closed by a gate valve 12g. The gate
valve 12g is provided along the sidewall of the chamber body
12.
[0028] A support 13 is provided on a bottom portion of the chamber
body 12. The support 13 is made of an insulating material. The
support 13 has a substantially cylindrical shape. The support 13
extends upward in the internal space 10s from the bottom portion of
the chamber body 12. The support 13 supports a substrate support
14. The substrate support 14 is provided in the chamber 10. The
substrate support 14 is configured to support the substrate W in
the internal space 10s.
[0029] The substrate support 14 has a lower electrode 18 and an
electrostatic chuck 20. The substrate support 14 may further
include an electrode plate 16. The electrode plate 16 is made of a
conductor such as aluminum and has a substantially disk shape. The
lower electrode 18 is provided on the electrode plate 16. The lower
electrode 18 is made of a conductor such as aluminum and has a
substantially disk shape. The lower electrode 18 is electrically
connected to the electrode plate 16.
[0030] The electrostatic chuck 20 is provided on the lower
electrode 18. The substrate W is placed on an upper surface of the
electrostatic chuck 20. The electrostatic chuck 20 has a main body
and an electrode. The main body of the electrostatic chuck 20 has a
substantially disk shape and is made of a dielectric material. The
electrode of the electrostatic chuck 20 is an electrode in the form
of a film and provided in the main body of the electrostatic chuck
20. The electrode of the electrostatic chuck 20 is connected to a
direct current power source 20p through a switch 20s. Electrostatic
attractive force is generated between the electrostatic chuck 20
and the substrate W when a voltage is applied to the electrode of
the electrostatic chuck 20 from the direct current power source
20p. The substrate W is held by the electrostatic chuck 20 by the
electrostatic attractive force.
[0031] An edge ring 25 is disposed on a circumferential edge
portion of the substrate support 14 to surround an edge of the
substrate W. The edge ring 25 may improve in-plane uniformity of
the plasma processing performed on the substrate W. The edge ring
25 may be made of for example, silicon, silicon carbide, or
quartz.
[0032] A flow path 18f is provided in the lower electrode 18. A
heat exchange medium (e.g., coolant) is supplied into the flow path
18f through a pipe 22a from a chiller unit 22 (not shown) provided
outside the chamber 10. The heat exchange medium supplied into the
flow path 18f returns back to the chiller unit through the pipe
22b. In the plasma processing apparatus 1, a temperature of the
substrate W placed on the electrostatic chuck 20 is adjusted by
heat exchange between the heat exchange medium and the lower
electrode 18.
[0033] In an embodiment, the substrate support 14 may further have
a heater HT. The heater HT is provided in the substrate support 14
to heat the substrate W. The heater HT may be provided in the
electrostatic chuck 20. Electric power is supplied from a heater
controller HC to the heater HT. The heater controller HC is
configured to adjust an amount of electric power of the heater
HT.
[0034] In the plasma processing apparatus 1, a gas supply line 24
is provided. The gas supply line 24 supplies heat transfer gas
(e.g., He gas) from a heat transfer gas supply mechanism to a
portion between an upper surface of the electrostatic chuck 20 and
a rear surface of the substrate W.
[0035] The plasma processing apparatus 1 further includes an upper
electrode 30. The upper electrode 30 is provided above the
substrate support 14. The upper electrode 30 is supported at an
upper portion of the chamber body 12 via a member 32. The member 32
is made of an insulating material. The upper electrode 30 and the
member 32 close an upper opening of the chamber body 12.
[0036] The upper electrode 30 may include a ceiling plate 34 and a
support 36. A lower surface of the ceiling plate 34, which is a
lower surface directed toward the internal space 10s, defines the
internal space 10s. The ceiling plate 34 may be made of a
semiconductor material or a low-resistance conductor, in which low
Joule heat is generated. The ceiling plate 34 has a plurality of
gas discharge holes 34a that penetrate in a direction of a plate
thickness of the ceiling plate 34.
[0037] The support body 36 detachably supports the ceiling plate
34. The support body 36 is made of a conductive material such as
aluminum. A gas diffusion space 36a is provided in the support body
36. The support body 36 has a plurality of gas holes 36b that
extend downward from the gas diffusion space 36a. The gas holes 36b
are in communication with the gas discharge holes 34a respectively.
A gas introduction port 36c is formed in the support body 36. The
gas introduction port 36c is connected to the gas diffusion space
36a. A gas supply pipe 38 is connected to the gas introduction port
36c.
[0038] A gas source group 40 is connected to the gas supply pipe 38
through a flow rate controller group 41 and a valve group 42. The
gas source group 40 includes a plurality of gas sources. The flow
rate controller group 41 includes a plurality of flow rate
controllers. Each of the flow rate controllers of the flow rate
controller group 41 is a mass flow controller or a pressure-control
flow rate controller. The valve group 42 includes a plurality of
on-off valves. Each of the gas sources of the gas source group 40
is connected to the gas supply pipe 38 through a corresponding flow
rate controller of the flow rate controller group 41 and a
corresponding on-off valve of the valve group 42. The gas source
group 40, the flow rate controller group 41, and the valve group 42
constitute a gas supply unit. The gas supply unit is configured to
supply a first processing gas and a second processing gas, which
will be described later, into the chamber 10
[0039] In the plasma processing apparatus 1, a shield 46 is
detachably provided along the inner wall surface of the chamber
body 12 and an outer circumference of the support 13. The shield 46
prevents reactive by-product from being attached to the chamber
body 12. The shield 46 is formed by forming a corrosion-resistant
film on a surface of a base member made of, for example, aluminum.
The corrosion-resistant film may be ceramics such as yttrium
oxide.
[0040] A baffle plate 48 is provided between the support 13 and the
sidewall of the chamber body 12. The baffle plate 48 is formed by
forming a corrosion-resistant film (e.g. a film such as yttrium
oxide film) on a surface of a base member such as aluminum. The
baffle plate 48 has a plurality of through holes. A gas discharge
port 12e is provided below the baffle plate 48 and in the bottom
portion of the chamber body 12. An exhaust device 50 is connected
to the gas discharge port 12e through a gas discharge pipe 52. The
exhaust device 50 includes a pressure control valve and a vacuum
pump such as a turbo molecular pump.
[0041] The plasma processing apparatus 1 includes a first
radio-frequency power source 62 and a second radio frequency power
source 64. The first radio frequency power source 62 is a power
source that generates first radio frequency power. The first radio
frequency electric power has a frequency suitable for generating
plasma. The frequency of the first radio frequency power is, for
example, a frequency within a range of 27 MHz to 100 MHz. The first
radio frequency power source 62 is connected to the lower electrode
18 through a matcher 66 and the electrode plate 16. The matcher 66
has a circuit for matching impedance at a load side (lower
electrode 18 side) of the first radio frequency power source 62
with output impedance of the first radio frequency power source 62.
In another example, the first radio frequency power source 62 may
be connected to the upper electrode 30 through the matcher 66. The
first radio frequency power source 62 constitutes an example of a
plasma producing unit.
[0042] The second radio frequency power source 64 is a power source
that generates second radio frequency electric power. The second
radio frequency electric power has a frequency lower than the
frequency of the first radio frequency electric power. When the
second radio frequency electric power is used together with the
first radio frequency electric power, the second radio frequency
electric power is used as bias radio frequency electric power for
attracting ions to the substrate W. The frequency of the second
radio frequency electric power is, for example, a frequency within
a range of 400 kHz to 13.56 MHz. The second radio frequency power
source 64 is connected to the lower electrode 18 through a matcher
68 and the electrode plate 16. The matcher 68 has a circuit for
matching impedance at a load side (lower electrode 18 side) of the
second radio frequency power source 64 with output impedance of the
second radio frequency power source 64.
[0043] The plasma may be produced by using the second radio
frequency electric power without using the first radio frequency
electric power, that is, by using only single radio frequency
electric power. In such a case, the frequency of the second radio
frequency electric power may be a frequency higher than 13.56 MHz,
for example, a frequency of 40 MHz. In such a case, the plasma
processing apparatus 1 may have neither the first radio frequency
power source 62 nor the matching device 66. In such a case, the
second radio frequency power source 64 constitutes an example of
the plasma producing unit.
[0044] In the plasma processing apparatus 1, gas is supplied into
the internal space 10s from the gas supply unit to produce the
plasma. In addition, the first radio frequency electric power
and/or the second radio frequency electric power is supplied to
produce a radio frequency electric field between the upper
electrode 30 and the lower electrode 18 as. The produced radio
frequency electric field produces plasma.
[0045] The plasma processing apparatus 1 may further include a
controller 80. The controller 80 may be a computer including, for
example, a processor, a storage unit such as a memory, an input
device, a display device, and a signal input-output interface. The
controller 80 controls respective parts of the plasma processing
apparatus 1. The controller 80 may allow an operator to perform an
operation of inputting a command to manage the plasma processing
apparatus 1 by using the input device. In addition, the controller
80 may visibly display an operational situation of the plasma
processing apparatus 1 through the display device. Further, the
storage unit stores a control program and recipe data. The control
program is executed by the processor to perform various types of
processing in the plasma processing apparatus 1. The processor
executes the control program and controls the respective parts of
the plasma processing apparatus 1 in accordance with the recipe
data.
[0046] Hereinafter, the method MT will be described in detail with
reference to FIG. 1 again. Hereinafter, the method MT will be
described by taking as an example the case where the steps STa to
STd, the step ST1, and the step ST2 are applied to the substrate W
shown in FIG. 3. Further, in the following description, FIG. 5A,
FIG. 5B, FIG. 6, FIG. 7A, and FIG. 7B are also referred to. FIG.
5A, FIG. 5B, FIG. 6, FIG. 7A, and FIG. 7B are respectively
partially enlarged cross-sectional views of exemplary substrates in
a state after performing the step STa, the step STb, the step STc,
the step ST1, and the step ST2 of the method shown in FIG. 1.
[0047] In the step STa, the antireflection film is etched by plasma
etching in order to transfer the pattern of the resist mask RM to
the antireflection film AF. In the step STa, plasma is generated
from a processing gas in the chamber 10. The processing gas used in
the step STa may include an oxygen-containing gas (for example,
oxygen gas). Alternatively, the processing gas used in the step STa
may include a nitrogen gas and a hydrogen gas. In the step STa, the
antireflection film AF is etched by the chemical species from the
generated plasma. As a result, as shown in FIG. 5A, the pattern of
the resist mask RM is transferred to the antireflection film
AF.
[0048] In order to perform the step STa, the controller 80 controls
the gas supply unit to supply the processing gas into the chamber
10. In order to perform the step STa, the controller 80 controls
the exhaust device 50 to set the pressure inside the chamber 10 to
the designated pressure. In order to perform the step STa, the
controller 80 controls the first radio frequency power supply 62
and/or the second radio frequency power supply 64 to supply the
first radio frequency power and/or the second radio frequency
power.
[0049] In the subsequent step STb, the SiON film SF is etched by
plasma etching in order to transfer the pattern of the
antireflection film AF to the SiON film SF. In the step STb, plasma
is generated from a processing gas in the chamber 10. The
processing gas used in the step STb includes a hydrofluorocarbon
gas. The processing gas used in the step STb may further include a
fluorocarbon gas. The processing gas used in the step STb may
further include other gas such as an oxygen gas and/or a rare gas.
In the step STb, the SiON film SF is etched by the chemical species
from the generated plasma. As a result, as shown in FIG. 5B, the
pattern of the antireflection film AF is transferred to the SiON
film SF.
[0050] In order to perform the step STb, the controller 80 controls
the gas supply unit to supply the processing gas into the chamber
10. In order to perform the step STb, the controller 80 controls
the exhaust device 50 to set the pressure inside the chamber 10 to
the designated pressure. In order to perform the step STb, the
controller 80 controls the first radio frequency power supply 62
and/or the second radio frequency power supply 64 to supply the
first radio frequency power and/or the second radio frequency
power.
[0051] In the subsequent step STc, the organic film OF is etched by
plasma etching in order to transfer the pattern of the SiON film SF
to the organic film OF. In the step STc, plasma is generated from a
processing gas in the chamber 10. The processing gas used in the
step STc may include an oxygen-containing gas (for example, oxygen
gas). Alternatively, the processing gas used in the step STc may
include nitrogen gas and hydrogen gas. In the step STc, the organic
film OF is etched by the chemical species from the generated
plasma. As a result, as shown in FIG. 6, the pattern of the SiON
film SF is transferred to the organic film OF, and the mask MK is
formed from the organic film OF. While performing the step STc, the
resist mask RM and the antireflection film AF are removed by the
chemical species from the plasma.
[0052] In order to perform the step STc, the controller 80 controls
the gas supply unit to supply the processing gas into the chamber
10. In order to perform the step STc, the controller 80 controls
the exhaust device 50 to set the pressure inside the chamber 10 to
the designated pressure. In order to perform the step STc, the
controller 80 controls the first radio frequency power supply 62
and/or the second radio frequency power supply 64 to supply the
first radio frequency power and/or the second radio frequency
power.
[0053] In the subsequent step STd, the SiON film SF is removed. In
the step STd, plasma is generated from a processing gas in the
chamber 10. The processing gas used in the step STd includes a
hydrofluorocarbon gas. The processing gas used in the step STd may
further include a fluorocarbon gas. The processing gas used in the
step STd may further include other gas such as an oxygen gas and/or
a rare gas. In the step STd, the SiON film SF is etched and removed
by the chemical species from the generated plasma. As a result, the
substrate W shown in FIG. 2 is obtained.
[0054] In order to perform the step STd, the controller 80 controls
the gas supply unit to supply the processing gas into the chamber
10. In order to perform the step STd, the controller 80 controls
the exhaust device 50 to set the pressure inside the chamber 10 to
the designated pressure. In order to perform the step STd, the
controller 80 controls the first radio frequency power supply 62
and/or the second radio frequency power supply 64 to supply the
first radio frequency power and/or the second radio frequency
power.
[0055] In the subsequent step ST1, the first plasma processing is
performed. That is, in the step ST1, the substrate W is processed
using the first plasma formed from the first processing gas. The
first processing gas includes a fluorocarbon gas, a fluorine-free
carbon-containing gas, and an oxygen-containing gas. The
fluorocarbon gas in the first processing gas is a gas composed of
any molecule represented by C.sub.XF.sub.Y. The fluorocarbon gas
is, for example, C.sub.4F.sub.6 gas. In the first processing gas,
the fluorine-free carbon-containing gas is, for example, CO gas or
CO.sub.2 gas. The oxygen-containing gas in the first processing gas
is an oxygen gas, for example. In the step ST1, plasma is generated
from the first processing gas in the chamber 10.
[0056] In the step ST1, the temperature of the substrate W is set
to the first temperature. The first temperature is lower than the
second temperature which is the temperature of the substrate W in
the step ST2. The first temperature is, for example, a temperature
lower than 50.degree. C. In an embodiment, in order to set the
temperature of the substrate W to the first temperature in the step
ST1, the first radio frequency power is set to be lower than the
first radio frequency power used in the step ST2. In a case where a
small radio frequency power is used, the density of the plasma
becomes low and the amount of heat given to the substrate W from
the plasma becomes small. According to the embodiment, the
temperature of the substrate W is set to the first temperature
while performing the first plasma processing by adjusting at least
the radio frequency power.
[0057] In another embodiment, the temperature of the substrate W
during the first plasma processing may be set to the first
temperature by adjusting the amount of electric power of the heater
HT. Further, in another embodiment, the temperature of the
substrate W in the step ST1 may be set to the first temperature
through both the adjustment of the first radio frequency power and
the adjustment of the amount of electric power of the heater
HT.
[0058] In a case where the temperature of the substrate W is set to
a relatively low temperature, a relatively large amount of
carbon-containing material is deposited on the surface of the
substrate W from the first plasma. Therefore, as a result of the
first plasma processing, a relatively large amount of the
carbon-containing material DP is deposited on the mask MK, as shown
in FIG. 7A. Further, while performing the first plasma processing,
the silicon oxide film OX is etched by the fluorine species from
the first plasma.
[0059] In order to perform the step ST1, the controller 80 controls
the gas supply unit to supply the first processing gas into the
chamber 10. In order to perform the step ST1, the controller 80
controls the exhaust device 50 to set the pressure inside the
chamber 10 to the designated pressure. In order to perform the step
ST1, the controller 80 controls the first radio frequency power
supply 62 and the second radio frequency power supply 64 to supply
the first radio frequency power and the second radio frequency
power. In the step ST1, one of the first radio frequency power and
the second radio frequency power may not be supplied. Moreover, in
order to set the temperature of the substrate W to the first
temperature in the step ST1, the controller 80 controls the first
radio frequency power supply 62 and/or the heater controller
HC.
[0060] The step ST2 is performed after the step ST1. In the step
ST2, the second plasma processing is performed. That is, in the
step ST2, the substrate W is processed using the second plasma
formed from the second processing gas. The second processing gas is
a gas including a fluorocarbon gas. In an embodiment, the second
processing gas may be the same gas as the first processing gas.
That is, the second processing gas may include a fluorocarbon gas,
a fluorine-free carbon-containing gas, and an oxygen-containing
gas. The fluorocarbon gas in the second processing gas is a gas
composed of any molecule represented by C.sub.XF.sub.Y. The
fluorocarbon gas is, for example, C.sub.4F.sub.6 gas. In the second
processing gas, the fluorine-free carbon-containing gas is, for
example, CO gas or CO.sub.2 gas. The oxygen-containing gas in the
second processing gas is an oxygen gas, for example. In the step
ST2, plasma is generated in the chamber 10 from the second
processing gas.
[0061] In the step ST2, the temperature of the substrate W is set
to the second temperature. The second temperature is higher than
the first temperature which is the temperature of the substrate W
in the step ST1. The second temperature is, for example, a
temperature equal to or higher than 50.degree. C. In an embodiment,
in order to set the temperature of the substrate W to the second
temperature in the step ST2, the first radio frequency power is set
to be higher than the first radio frequency power used in the step
ST.
[0062] In another embodiment, the temperature of the substrate W
during the second plasma processing may be set to the second
temperature by adjusting the amount of electric power of the heater
HT. Further, in another embodiment, the temperature of the
substrate W in the step ST2 may be set to the second temperature
through both the adjustment of the first radio frequency power and
the adjustment of the amount of electric power of the heater
HT.
[0063] While performing the second plasma processing, the silicon
oxide film OX is further etched by the fluorine species from the
second plasma. On the other hand, the mask MK is protected while
performing the second plasma processing by the carbon-containing
material DP deposited on the mask MK as a result of the first
plasma processing (refer to FIG. 7B). Hence, according to the
method MT, it is possible to suppress the decrease in film
thickness of the mask MK due to the etching of the silicon oxide
film OX.
[0064] In order to perform the step ST2, the controller 80 controls
the gas supply unit to supply the second processing gas into the
chamber 10. In order to perform the step ST2, the controller 80
controls the exhaust device 50 to set the pressure inside the
chamber 10 to the designated pressure. In order to performed the
step ST2, the controller 80 controls the first radio frequency
power supply 62 and the second radio frequency power supply 64 to
supply the first radio frequency power and the second radio
frequency power. Moreover, in order to set the temperature of the
substrate W to the second temperature in the step ST2, the
controller 80 controls the first radio frequency power supply 62
and/or the heater controller HC.
[0065] While various exemplary embodiments have been described
above, various additions, omissions, substitutions and changes may
be made without being limited to the exemplary embodiments
described above. Elements of the different embodiments may be
combined to form another embodiment.
[0066] For example, at least one of the step STa, the step STb, the
step STc, the step STd, the step ST1, or the step ST2 of the method
IT may be performed using a plasma processing apparatus different
from the plasma processing apparatus used in other steps of the
method MT.
[0067] Further, a capacitively coupled plasma processing apparatus
different from the plasma processing apparatus 1 or a different
type of plasma processing apparatus may be used to performed the
method MT. Examples of the different type of plasma processing
apparatus include a capacitively coupled plasma processing
apparatus and a plasma processing apparatus that excites gas by
using surface waves such as microwaves.
[0068] From the foregoing description, it will be appreciated that
various embodiments of the present disclosure have been described
herein for purposes of illustration, and that various modifications
may be made without departing from the scope and spirit of the
present disclosure. Accordingly, the various embodiments disclosed
herein are not intended to be limiting, with the true scope and
spirit being indicated by the following claims.
* * * * *